1. Field of the Invention
The invention relates to an operating device for motor vehicles.
2. Discussion of the Prior Art
Friction clutches are subjected to constant wear which makes it necessary to replace the clutch disks at the right time, it generally being desirable to render the wear visible without dismantling the entire clutch. Lever-operated clutches, in which the lever is mechanically joined to the coupling disk, permit direct measurement of the wear at the lever. In the case of actuating a clutch via a hydraulic cylinder, it is no longer the lever position for clutch operation but the position of the hydraulic piston which is a measure of the rate of wear on the clutch disk.
A device is described in German reference DE 41 20 643 A1 which displays the wear by means of an electric contact on the hydraulic cylinder, and thus displays the position of the hydraulic piston. The display is installed in the form of a warning lamp which informs the user of the motor vehicle about the state of the clutch.